1. Field of the Invention
This invention relates in general to flush valves for water closets, urinals and other plumbing equipment. More particularly, the invention relates to an improved diaphragm for use in flush valves.
2. Description of the Prior Art
Flush valves in water closets, urinals and other plumbing devices which utilize a flexible diaphragm to establish and to seal off the connection between the inlet and outlet are well-known in the art. Typically, the diaphragm is made of an elastomeric material, such as rubber, and includes a bypass which provides fluid communication between the inlet side of the flush valve and an upper chamber of the flush valve. A typical prior art diaphragm is shown in FIG. 1 of U.S. Pat. No. 5,232,194 to Saadi et al. (hereinafter xe2x80x9cthe Saadi patentxe2x80x9d), and is incorporated herein by reference.
The Saadi patent also discloses a unitary diaphragm assembly that includes a diaphragm having a cylindrically-shaped bypass orifice formed therein and is illustrated in FIGS. 2 and 3 of the present patent application.
The performance of prior art diaphragms varies depending on the pressure drop between the opposite sides of the diaphragm due to the bypass orifice. Specifically, a higher pressure difference across the diaphragm, such as will occur on a bottom floor of a multistory building, causes more water to pass through the flush valve for a fixed period of time when the flush valve is activated. Likewise, in a situation where there is a low pressure difference across the diaphragm, less water will flow through the flush valve when it is activated. Hence, the amount of water flowing through the flush valve is a function of the supply of water pressure to the flush valve.
Therefore, it is an object of the present invention to provide an improved diaphragm orifice to compensate for pressure differentials across the diaphragm and improve valve performance.
The present invention is a barrier for separating fluid and is configured to have a pressure difference applied across the barrier. The barrier includes a flexible diaphragm having a first side and a second side and defines an orifice extending from the first side to the second side. The orifice has a first end defined in the first side and a second end defined in the second side of the diaphragm. The first end has a diameter less than the diameter of the second end. The second end of the diaphragm is concave and the first side of the diaphragm is convex when the pressure difference is applied across the barrier whereby the diameter of the first end increases.
The present invention is also a diaphragm orifice for a valve such as a flush valve. The flush valve made in accordance with the present invention generally includes a valve body defining an inlet connection and an outlet connection, and a unitary diaphragm assembly positioned in the valve body. The unitary diaphragm assembly separates and seals off the inlet connection from the outlet connection. The unitary diaphragm assembly is configured to have a pressure difference applied across the assembly.
The unitary diaphragm assembly further includes a flexible diaphragm. The flexible diaphragm has a mounting portion at a peripheral edge for mounting the diaphragm assembly within the flush valve. The diaphragm has a first side and a second side and defines an orifice extending from the first side to the second side. The orifice has a first end defined in the first side and a second end defined in the second side of the diaphragm. The first end has a diameter less than the diameter of the second end. The orifice extends from the first end to the second end. The second side of the diaphragm is concave and the first side of the diaphragm is convex when the pressure difference is applied across the assembly whereby the diameter of the first end increases.
The first end of the orifice is defined by a first portion of the diaphragm. The second end of the orifice is defined by a second portion of the diaphragm. The second portion is positioned adjacent the first portion. The first portion includes a tapered surface that preferably extends at an angle of about 45xc2x0 from a horizontal plane passing through the diaphragm. Preferably the diaphragm is made of an elastomeric material, such as rubber or a thermoplastic elastomer resin, and is flexible.
The diaphragm of the unitary diaphragm assembly may be annular-shaped and may have a sealing surface. The unitary diaphragm assembly may further include a flow ring adjacent the sealing surface. An elongated barrel member may be formed adjacent the flow ring. The barrel member may have a first end or top end. A plurality of radial guides may be formed circumferentially around an outer surface of the barrel member and may extend along at least a portion of a longitudinal length of the barrel member. Additionally, the unitary diaphragm assembly may include a relief valve seat at the first end of the barrel member. The relief valve seat may be configured to seal against a relief valve of the flush valve.
In operation, a pressure difference across the diaphragm causes the diaphragm to flex. A greater pressure difference across the diaphragm will cause the diaphragm to flex more than a lesser pressure difference. The amount of flex affects the pressure sensitivity of the flush valve and improves the overall performance of the flush valve. Further, the flexing improves the flush valve""s resistance to clogging. The flexing action can free debris that would normally clog a non-elastomeric orifice. Examples of this debris include sediment and water deposits such as scale.
The present invention is also a method of compensating for a pressure difference across the barrier discussed above. The method includes the steps of applying the pressure difference across the diaphragm and flexing the diaphragm. The pressure difference is applied such that pressure on the first side of the diaphragm is lower than the pressure on the second side of the diaphragm. The diaphragm is flexed such that the second side of the diaphragm is concave and the first side of the diaphragm is convex whereby the diameter of the first end increases and fluid flows through the orifice. The method may also include the step of positioning the diaphragm in the flush valve discussed above between the inlet connection and the outlet connection of the flush valve.